Left atrial anatomy relevant to catheter ablation

The rapid development of interventional procedures for the treatment of arrhythmias in humans, especially the use of catheter ablation techniques, has renewed interest in cardiac anatomy. Although the substrates of atrial fibrillation (AF), its initiation and maintenance, remain to be fully elucidated, catheter ablation in the left atrium (LA) has become a common therapeutic option for patients with this arrhythmia. Using ablation catheters, various isolation lines and focal targets are created, the majority of which are based on gross anatomical, electroanatomical, and myoarchitectual patterns of the left atrial wall. Our aim was therefore to review the gross morphological and architectural features of the LA and their relations to extracardiac structures. The latter have also become relevant because extracardiac complications of AF ablation can occur, due to injuries to the phrenic and vagal plexus nerves, adjacent coronary arteries, or the esophageal wall causing devastating consequences.

Hallazgos tomográficos como predictores del resultado funcional en edema macular secundario a oclusiones venosas retinianas

INTRODUCCIÓN: El Edema Macular (EM) es la principal causa de perdida de agudeza visual en pacientes con Oclusión Venosa Retiniana (OVR); luego del tratamiento, algunos pacientes persisten con mala agudeza visual. OBJETIVO: Realizar una Revisión Sistemática de la Literatura (RSL), para identificar la evidencia existente sobre factores tomográficos que predicen el resultado visual en pacientes con EM secundario a OVR. FUENTE DE LA INFORMACIÓN: PUBMED, MEDLINE, EMBASE, LILACS, COCHRANE, literatura gris. SELECCIÓN DE LOS ESTUDIOS: Ensayos Clínicos Controlados (ECC) y estudios observacionales analíticos. EXTRACCIÓN Y SÍNTESIS DE LOS DATOS: Dos investigadores seleccionaron los artículos de forma independiente. Se realizó una síntesis cualitativa de la información siguiendo las recomendaciones de la declaración PRISMA 2009. MEDIDAS Y DESENLACE PRINCIPAL: Grosor Retiniano Central (GRC), integridad de Banda Elipsoide e Integridad de Membrana Limitante Externa (MLE), determinados por SD OCT. El desenlace principal es la Agudeza Visual Mejor Corregida (AVMC) a los 6, 12,18 y/o 24 meses. RESULTADOS: Se identificaron 872 abstract y se incluyeron 8 artículos en el análisis cualitativo. Seis estudios evaluaron el GRC sin encontrar asociación con resultado visual final. Solo 2 estudios evaluaron y encontraron asociación estadísticamente significativa de la integridad de la MLE con el desenlace visual, Kang, H 2012 (r2 0,51 p 0,000), Rodriguez, F 2014 (p< 0,001). La integridad de la BE fue asociada a pronostico visual en 4 de 5 estudios que evaluaron esta variable, con resultados estadísticamente significativos. La AVMC de base también se asocio con desenlace visual en 4 de 5 estudios que la evaluaron. El mejor modelo que predice el resultado funcional según el estudio de Kang, H 2012 fue: Integridad de MLE, integridad de BE y AVMC de base (R2 0,671 p 0,000), a los 12 meses de seguimiento. CONCLUSION: La evidencia actual sugiere que la integridad de la BE y la MLE son predictores del resultados funcional en pacientes con EM secundario a OVR después de 6 o mas meses de seguimiento. Es necesario la realización de estudios controlados para llegar a resultados mas concluyentes.

Interspecies study of the enteric nervous system and related pathologies

The enteric nervous system (ENS) modulates a number of digestive functions including well known ones, i.e. motility, secretion, absorption and blood flow, along with other critically relevant processes, i.e. immune responses of the gastrointestinal (GI) tract, gut microbiota and epithelial barrier . The characterization of the anatomical aspects of the ENS in large mammals and the identification of differences and similarities existing between species may represent a fundamental basis to decipher several digestive GI diseases in humans and animals. In this perspective, the aim of the present thesis is to highlight the ENS anatomical basis and pathological aspects in different mammalian species, such as horses, dogs and humans. Firstly, I designed two anatomical studies in horses:  “Excitatory and inhibitory enteric innervation of horse lower esophageal sphincter”.  “Localization of 5-hydroxytryptamine 4 receptor (5-HT4R) in the equine enteric nervous system”. Then I focused on the enteric dysfunctions, including:  A primary enteric aganglionosis in horses: “Extrinsic innervation of the ileum and pelvic flexure of foals with ileocolonic aganglionosis”.  A diabetic enteric neuropathy in dogs: “Quantification of nitrergic neurons in the myenteric plexus of gastric antrum and ileum of healthy and diabetic dogs”.  An enteric neuropathy in human neurological patients: “Functional and neurochemical abnormalities in patients with Parkinson's disease and chronic constipation”. The physiology of the GI tract is characterized by a high complexity and it is mainly dependent on the control of the intrinsic nervous system. ENS is critical to preserve body homeostasis as reflect by its derangement occurring in pathological conditions that can be lethal or seriously disabling to humans and animals. The knowledge of the anatomy and the pathology of the ENS represents a new important and fascinating topic, which deserves more attention in the veterinary medicine field.

Unraveling the pathophysiological mechanisms of visceral pain in the murine model of Fabry disease

Fabry disease (FD) is an X‐linked inherited, lysosomal storage disorder characterized by a deficient activity of the enzyme α-Galactosidase A (α-Gal A). This deficiency causes an accumulation of globotriaosylceramide 3 (Gb3), in nearly all organs. Gastrointestinal (GI) symptoms are among the earliest and most frequent symptoms of FD. It has been hypothesized that Gb3 accumulation is the leading cause of these, but their pathophysiology is complex and still poorly understood. Here, we aim at understanding the molecular mechanisms underpinning the GI symptoms of FD. For this purpose, we used the α‐Gal A (-/0) male mouse, a murine model of FD, to characterize morphological and molecular features of the colon tract. Our results show that α‐Gal A (-/0) mice display a thickening of the muscular layer due to a hypertrophic state of myenteric plexus ganglia, caused by an accumulation of Gb3 in neurons. Also, α-Gal A (-/0) mice present a decreased density of mucosal nerve fibres. Furthermore, α-Gal A (-/0) mice presented visceral hyperalgesia, by showing greater visceromotor response (VMR) values and obtaining higher abdominal withdrawal reflex (AWR) scores, following colorectal distension (CRD). Subsequently, the immunoreactivity of the pain-related ion channels TRPV1, TRPV4, TRPA1 and TRPM8 was detected at level of myenteric and submucosal plexus ganglia of both the genotypes. Further studies are required to assess differences of expression between α-Gal A (-/0) and control mice. Finally, we optimized the protocols to obtain three types of primary cultures from mouse intestine to be tested electrophysiologically: a mixed culture containing neurons and glia, an enriched culture of neurons, and one of glia. In summary, we revealed alterations that are likely to be part of the pathophysiological causes of FD GI symptoms. Therefore, together with further studies, this work could help identify new therapeutic targets for the treatment of visceral pain in FD.